AI 中文总结
本文通过多种理论计算发现，超导La₅Ni₃O₁₁中的插层La₂NiO₄层为电子非活性，其低能电子结构主要由La₃Ni₂O₇块体主导，为相关镍酸盐超导研究提供了统一框架。
AI 中文摘要
近期在La₅Ni₃O₁₁中发现的超导性，将超导Ruddlesden–Popper型镍酸盐家族扩展至La₃Ni₂O₇之外。与单一Ruddlesden–Popper系列的常规成员不同，La₅Ni₃O₁₁在La₃Ni₂O₇块体之间包含一层插层La₂NiO₄，这引发了一个问题：该额外层是否参与低能电子结构。本文结合密度泛函理论、基于Wannier的紧束缚模型以及旋转不变的slave-boson计算，研究了该插层的电子作用。研究发现，实际电子参数使La₂NiO₄层处于带隙绝缘态，而非顺磁金属态；此外，实际层间杂化未在费米能级产生任何可观测的La₂NiO₄衍生谱权重。结果表明，La₅Ni₃O₁₁的低能电子结构主要由La₃Ni₂O₇块体主导，插层La₂NiO₄层保持电子非活性。这建立了La₅Ni₃O₁₁的最小低能描述，为理解插层Ruddlesden–Popper型镍酸盐的超导性提供了统一框架。
英文摘要
The recent discovery of superconductivity in La$_5$Ni$_3$O$_{11}$ extends the family of superconducting Ruddlesden--Popper nickelates beyond La$_3$Ni$_2$O$_7$. Unlike conventional members of a single Ruddlesden--Popper series, La$_5$Ni$_3$O$_{11}$ contains an intercalated La$_2$NiO$_4$ layer between La$_3$Ni$_2$O$_7$ blocks, raising the question of whether this additional layer participates in the low-energy electronic structure. Here, we combine density functional theory, Wannier-based tight-binding modeling, and rotationally invariant slave-boson calculations to investigate the electronic role of the intercalated layer. We find that realistic electronic parameters place the La$_2$NiO$_4$ layer in gapped insulating regimes rather than a paramagnetic metallic state. Furthermore, realistic interlayer hybridization fails to generate any appreciable La$_2$NiO$_4$-derived spectral weight at the Fermi level. Our results demonstrate that the low-energy electronic structure of La$_5$Ni$_3$O$_{11}$ is governed primarily by the La$_3$Ni$_2$O$_7$ block, with the intercalated La$_2$NiO$_4$ layer remaining electronically inactive. This establishes a minimal low-energy description of La$_5$Ni$_3$O$_{11}$ and provides a unified framework for understanding superconductivity in intercalated Ruddlesden--Popper nickelates.
Comments11 pages, 7 figures
